A. Field of the Disclosure
The invention relates generally to automatic utility meter systems. More specifically, the invention relates to an RFID-enabled utility device interface unit configured to receive measurements from a utility meter.
B. Background
Meters that measure utility usage are widely used to keep track of the consumption of an end user. For example, utility companies that supply water to their customers typically charge for their product based on usage. Usage of water is typically measured by a meter that is installed for each individual customer on their respective water supply line. Traditionally, utility company employees periodically (usually monthly) manually collect readings from meters. These readings are usually cumulative, so the amount of usage for the present period is calculated by subtracting the reading from the previous period. Once the usage is calculated, the customer is billed for that amount of water used during that period.
Manually reading usage meters is labor intensive, time consuming, expensive, and subject to human error, especially for residential customers because each meter monitors relatively little usage as compared with larger, commercial customers. As a result, meters combined with electronics have been used to allow for quicker, more efficient, and more accurate collection of usage data along with other pertinent information such as leak information or reverse flow detection. The electronic portion is referred to as a “meter interface unit” (MIU). The meter may still measure usage by monitoring flow through a conventional, mechanical meter. The usage readings are stored electronically by the MIU and then transmitted via radio signals to a local transmitter/receiver (transceiver) operated by the utility.
The most common types of transceivers for this purpose are mobile transceivers and fixed networks. Mobile transceivers are generally handheld or vehicle mounted. A utility employee drives or walks within the transmission range of the meter and the meter data is received and stored. The use of mobile transceivers has the advantage of bringing the transceiver close to the meter, therefore allowing the MIU to broadcast using less energy; however, transporting the transceiver from place to place is laborious. Fixed networks have the advantage of saving the cost and labor of bringing the transceiver close to the MIU, but they require that the MIU transmit its data using more energy so it can reach a distant transceiver.
The MIU often cannot be practically connected to the power grid, so it must rely on an alternative source of power, such as a battery. Batteries of course hold only a limited amount of power, and when depleted the battery must be replaced or recharged. Replacing and recharging batteries has not yet been automated, and requires human labor. If batteries must be replaced, the cost of replacement batteries can be significant for the utility district in the aggregate. The growing popularity of fixed networks to read meters means that MIUs must transmit using more power, reducing battery life. When the battery is expended, the MIU cannot communicate with the transceiver and usage data is lost. Loss of power of course is not unique to batteries, and may occur even in situations in which the MIU receives power from the grid.
Consequently there is a need in the art for technologies to allow data to be safely stored and recovered from an MIU without the use of a separate battery power source.